The invention concerns a process and the means, specifically a probe for DNA, for the detection of shigellae and entero-invasive strains of E. coli. It concerns more particularly, since it is in this case that it appears most promising, the means permitting in vitro diagnosis of the syndromes of dysenteries and diarrheas due to the kinds of bacteria in question whose capacity to invade the mucus cells of the colon and cause tissue damage, is well known. In a general manner, these afflictions will be hereafter referred to as shigelloses, whether they are actually due to shigellae or again to entero-inasive strains of E. coli which are nonetheless known to produce a dysentery of a similar type to those produced by the shigellae. It has, in addition, been noted that these strains of E. coli belong to various 0 serotypes which often give rise to cross-reactions with the A, B, and C serogroups of shigellae.
Shigelloses are endemic throughout the world. However, they present a particularly serious public health problem in tropical regions and developing countries where Shigella dysenteriae and S. flexneri predominate. In industrialized countries, the principal etiologic agent is S. sonnei although sporadic cases of shigellosis are encountered due to S. flexneri, S. boydii and the above-mentioned serotype of entero-invasive E. coli.
The severity of dysenteric syndromes calls for rapid diagnosis and treatment of the disease. The detection of the bacterial species needs also to depend on rapid, simple and low-cost procedures. Unfortunately, no such procedure is currently available. The processes for the identification of the bacterial species responsible imply relatively complicated tests for bacteriological or immunological virulence. One of these tests involves the induction of a kerato-conjunctivitis in a guinea pig by the virulent bacteria (Sereny, B. Acta Microbiol. Hung. [1957], 4, 367-376). Another test sometimes used involves in vitro colonization by these bacteria of mono-layers of human HeLa cells in culture according to the technique described by HALE, T.L. and FORMAL, F.D., Infect. Immun., 1981, 32, 137-144. It is obvious that these techniques are impractical for large-scale use for prevention or therapy.